E93.1001EN.C Manual CD
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16.2
Blocking codes
The display is not blinking, but is lightened up during the blocking period.
The water heater is blocking an action, because of an extraordinary situation. This action will be con-
tinued after eliminating the extraordinary situation.
Display message
A n t
i c y c l e
t
i m e
9 9 9 , 5
h r s
Reason
The heater received a heat demand too fast after the last demand.
Cause:
Opening and immediately thereafter closing of the external thermostat.
Corrective action:
Controlled water flow cools down too quickly after loss of heat demand.
Controlled water flow heats up too quickly after start of heat demand.
Immediately opening and closing of the external thermostat. Check switching differential
of the ON/OFF thermostat.
Controller settings need to be changed. Be aware that the standard settings work fine for
all common systems. When anti-cycling is active, because of immediate heating or cool-
ing of the controlled water flow/temperature, it concerns an unconventional system.
Display message
C a s c a d e
B l o c k
9 9 9 , 5
h r s
Reason
One of the water heaters of the cascade is in a lock-out.
Cause:
The unit is programmed in such a way that none of the heaters in a cascade will fire, if
one has a lockout. One unit has a lockout and therefore the whole cascade is blocked.
Corrective action:
Troubleshoot the fault of the unit in lock-out.
Display message
D e l
t a
D i
r e c t
b l
o c k
9 9 9 , 5
h r s
Reason
Temperature difference between flow and return has exceeded
the blocking value
Cause:
The water flow through the unit is too low.
Corrective action:
Check functioning of the pump.
Check/open all valves that might restrict the water flow through the unit.
Check for an external system pump that influences the flow through the unit.
Check if the system resistance exceeds the spare capacity of the unit pump.
Make sure the heat exchanger is clean. Heat exchanger fouling (partly blockage) will in-
crease the resistance causing the water flow to drop.
Display message
F l
o w
h i
g h
D H W
9 9 9 , 5
h r s
Reason:
Setpoint return (tank)temperature DHW (S3) is higher than set-
point heating = flow temperature (S1)
Cause:
Wrong setting of parameter: P6BA Heating setpoint below P6CA DHW setpoint
Corrective action:
Adjust the heating setpoint through the display: menu, settings, heating setpoint
Display message
F l o w
t e m p
h i g h
9 9 9 , 5
h r s
Reason:
Flow temperature has exceeded the blocking temperature, but it
has not exceeded the lock-out value.
Cause:
The water flow is restricted.
Corrective action:
Check functioning of the pump.
Check/open all valves that might restrict the water flow through the unit.
Check for an external system pump that influences the flow through the unit.
Check if the system resistance exceeds the spare capacity of the unit pump.
